The present invention relates to the use of certain consistency regulators in cosmetic and pharmaceutical formulations.
In general, cosmetic emulsions are composed of a fatty phase, which contains numerous raw materials, an aqueous phase, active materials and, if required, pigments, preservatives and coloring materials. In the fatty phase, in addition to emulsifiers, oil components and antioxidants, consistency regulators are employed to increase the viscosity and thus improve the consistency required for a stable emulsion system. Consistency regulators in water-in-oil emulsions, include, for example, beeswax, paraffin, petroleum jelly, microwax, as well as metal stearates. In oil-in-water emulsions it is customary to use spermaceti, fatty alcohols and glycerofatty acid esters.
One of the best known cosmetic waxes is beeswax which is utilized in creams, lipsticks and make-up. In addition, beeswax is employed in pharmaceutical formulations such as ointments. Due to the complex chemical composition of beeswax, the cosmetic chemist often encounters difficulties reproducing formulations. For this reason and the fact that there is an increasing shortage of beeswax, efforts to develop economically acceptable synthetic beeswax substitutes have intensified in recent years.
U.S. Pat. Nos. 3,745,033, 3,914,131 and 3,933,708, describe combinations of high-molecular, alkyl-substituted, branched monocarboxylic acids, microcrystalline petroleum waxes and glyceride mixtures as beeswax substitutes. It has been disclosed in the above-mentioned U.S. patents that esterification products of montanic acid, ethylene glycol and oxidized paraffin, as well as synthetic waxes obtained by the esterification of pentaerythritol with saturated fatty acids and maleic anhydride have been used as synthetic beeswax substitutes.
U.S. Pat. No. 3,073,706 refers to several esters of mono- and polycarboxylic acids with mono- and multivalent alcohols as synthetic wax components in floor care materials. U.S. Pat. No. 3,127,440 discloses the use of dialkyl esters (C.sub.30 -C.sub.60) of 1,4-dicarboxylic acids in hard wax formulations. U.S. Pat. No. 4,151,001 describes a beeswax substitute consisting of a polyester reaction product as obtained by the reaction under esterification conditions of aliphatic alcohols and a glycol compound.
The use of mono- and dicarboxylic-2-hydroxyalkylesters as emulsifiers in water-in-oil emulsions has also been proposed. German published patent application disclosure No. 2,757,278, describes the use of these hydroxyalkylesters as water-in-oil emulsifiers in cosmetic emulsions. Dicarboxylic acids are indicated to be especially preferred carboxylic acid components. When monocarboxylic acids are used, it is recommended to use hydroxyl-, halogen- or ether-group-substituted, short-chain compounds.
Although many of the above-mentioned and other known synthetic beeswax substitutes now readily available are adequate to produce effective non-aqueous formulations, many impair the stability of a formulation in emulsion systems containing water. Although some economically feasible synthetic beeswax substitutes are available, there continues to be a need for economical consistency regulators suitable for use in cosmetic and pharmaceutical formulations.
An object of the present invention is to produce a class of synthetic consistency regulators for cosmetic and pharmaceutical emulsions, which does not exhibit the disadvantages of many of the currently available materials and exerts a positive influence of the consistency of emulsions and decorative cosmetics without reducing the storage stability.